Changeset 729

Timestamp:

Sep 19, 2006 1:37:53 PM (18 years ago)

Author:

bennylp

Message:

Fixed race-condition/deadlock problems in the dialog/user agent layer
all the way up to PJSUA-API:

• standardized locking order: dialog then user agent, and dialog then PJSUA
• any threads that attempt to acquire mutexes in different order than above MUST employ retry mechanism (for an example, see acquire_call() in pjsua_call.c). This retry mechanism has also been used in the UA layer (sip_ua_layer.c) since it needs to lock user agent layer first before the dialog.
• introduced pjsip_dlg_try_inc_lock() and PJSUA_TRY_LOCK() to accomodate above.
• pjsua tested on Quad Xeon with 4 threads and 200 cps, so far so good.

Location:

pjproject/trunk

Files:

• pjsip-apps/src/pjsua/pjsua_app.c (modified) (1 diff)
• pjsip/include/pjsip/sip_dialog.h (modified) (1 diff)
• pjsip/include/pjsip/sip_ua_layer.h (modified) (1 diff)
• pjsip/include/pjsua-lib/pjsua_internal.h (modified) (1 diff)
• pjsip/src/pjsip/sip_dialog.c (modified) (3 diffs)
• pjsip/src/pjsip/sip_ua_layer.c (modified) (9 diffs)
• pjsip/src/pjsua-lib/pjsua_call.c (modified) (45 diffs)

pjproject/trunk/pjsip-apps/src/pjsua/pjsua_app.c

@@ -1197 +1197 @@
     PJ_UNUSED_ARG(timer_heap);
 
+    if (call_id == PJSUA_INVALID_ID) {
+        PJ_LOG(1,(THIS_FILE, "Invalid call ID in timer callback"));
+        return;
+    }
+    
     /* Add warning header */
     pjsua_msg_data_init(&msg_data);

pjproject/trunk/pjsip/include/pjsip/sip_dialog.h

@@ -357 +357 @@
 
 /**
+ * Try to acquire dialog's lock, but return immediately if lock can not
+ * be acquired.
+ *
+ * @param dlg               The dialog.
+ *
+ * @return                  PJ_SUCCESS if lock has been acquired.
+ */
+PJ_DECL(pj_status_t) pjsip_dlg_try_inc_lock( pjsip_dialog *dlg );
+
+/**
  * Unlock dialog and decrement temporary session counter. After this function
  * is called, dialog may be destroyed.

pjproject/trunk/pjsip/include/pjsip/sip_ua_layer.h

@@ -82 +82 @@
 
 /**
- * Lock the dialog's hash table. This function is normally called by
- * dialog code only.
- *
- * @return              PJ_SUCCESS on success or the appropriate error code.
- */
-PJ_DECL(pj_status_t) pjsip_ua_lock_dlg_table(void);
-
-
-/**
- * Unlock the dialog's hash table. This function is normally called by
- * dialog code only.
- *
- * @return              PJ_SUCCESS on success or the appropriate error code.
- */
-PJ_DECL(pj_status_t) pjsip_ua_unlock_dlg_table(void);
-
-
-/**
  * Destroy the user agent layer.
  *

pjproject/trunk/pjsip/include/pjsua-lib/pjsua_internal.h

@@ -258 +258 @@
 
 
-#if 0
-#define PJSUA_LOCK()        pj_mutex_lock(pjsua_var.mutex);
-#define PJSUA_UNLOCK()      pj_mutex_unlock(pjsua_var.mutex);
+#if 1
+#define PJSUA_LOCK()        pj_mutex_lock(pjsua_var.mutex)
+#define PJSUA_TRY_LOCK()    pj_mutex_trylock(pjsua_var.mutex)
+#define PJSUA_UNLOCK()      pj_mutex_unlock(pjsua_var.mutex)
 #else
 #define PJSUA_LOCK()
+#define PJSUA_TRY_LOCK()    PJ_SUCCESS
 #define PJSUA_UNLOCK()
 #endif

pjproject/trunk/pjsip/src/pjsip/sip_dialog.c

@@ -693 +693 @@
               dlg->sess_count));
 
-    pjsip_ua_lock_dlg_table();
-
     pj_mutex_lock(dlg->mutex_);
     dlg->sess_count++;
 
-    //pjsip_ua_unlock_dlg_table();
-
     PJ_LOG(6,(dlg->obj_name, "Leaving pjsip_dlg_inc_lock(), sess_count=%d", 
               dlg->sess_count));
 }
 
+/* Try to acquire dialog's mutex, but bail out if mutex can not be
+ * acquired immediately.
+ */
+PJ_DEF(pj_status_t) pjsip_dlg_try_inc_lock(pjsip_dialog *dlg)
+{
+    pj_status_t status;
+
+    PJ_LOG(6,(dlg->obj_name,"Entering pjsip_dlg_try_inc_lock(), sess_count=%d", 
+              dlg->sess_count));
+
+    status = pj_mutex_trylock(dlg->mutex_);
+    if (status != PJ_SUCCESS) {
+        PJ_LOG(6,(dlg->obj_name, "pjsip_dlg_try_inc_lock() failed"));
+        return status;
+    }
+
+    dlg->sess_count++;
+
+    PJ_LOG(6,(dlg->obj_name, "Leaving pjsip_dlg_try_inc_lock(), sess_count=%d", 
+              dlg->sess_count));
+
+    return PJ_SUCCESS;
+}
+
 
 /*
@@ -713 +733 @@
     PJ_LOG(6,(dlg->obj_name, "Entering pjsip_dlg_dec_lock(), sess_count=%d", 
               dlg->sess_count));
-
-    //pjsip_ua_lock_dlg_table();
 
     pj_assert(dlg->sess_count > 0);
@@ -726 +744 @@
         pj_mutex_unlock(dlg->mutex_);
     }
-
-    pjsip_ua_unlock_dlg_table();
 
     PJ_LOG(6,(THIS_FILE, "Leaving pjsip_dlg_dec_lock() (dlg=%p)", dlg));

pjproject/trunk/pjsip/src/pjsip/sip_ua_layer.c

@@ -210 +210 @@
 
 
-/**
- * Lock the dialog's hash table. This function is normally called by
- * dialog code only.
- *
- * @return              PJ_SUCCESS on success or the appropriate error code.
- */
-PJ_DEF(pj_status_t) pjsip_ua_lock_dlg_table(void)
-{
-    return pj_mutex_lock(mod_ua.mutex);
-}
-
-
-/**
- * Unlock the dialog's hash table. This function is normally called by
- * dialog code only.
- *
- * @return              PJ_SUCCESS on success or the appropriate error code.
- */
-PJ_DEF(pj_status_t) pjsip_ua_unlock_dlg_table(void)
-{
-    return pj_mutex_unlock(mod_ua.mutex);
-}
-
-
 /*
  * Get the endpoint where this UA is currently registered.
@@ -500 +476 @@
     pj_str_t *from_tag;
     pjsip_dialog *dlg;
+    pj_status_t status;
 
     /* Optimized path: bail out early if request is not CANCEL and it doesn't
@@ -509 +486 @@
         return PJ_FALSE;
     }
+
+retry_on_deadlock:
 
     /* Lock user agent before looking up the dialog hash table. */
@@ -586 +565 @@
     rdata->endpt_info.mod_data[mod_ua.mod.id] = dlg;
 
-    /* Lock the dialog */
+    /* Try to lock the dialog */
     PJ_LOG(6,(dlg->obj_name, "UA layer acquiring dialog lock for request"));
-    pjsip_dlg_inc_lock(dlg);
+    status = pjsip_dlg_try_inc_lock(dlg);
+    if (status != PJ_SUCCESS) {
+        /* Failed to acquire dialog mutex immediately, this could be 
+         * because of deadlock. Release UA mutex, yield, and retry 
+         * the whole thing once again.
+         */
+        pj_mutex_unlock(mod_ua.mutex);
+        pj_thread_sleep(0);
+        goto retry_on_deadlock;
+    }
+
+    /* Done with processing in UA layer, release lock */
+    pj_mutex_unlock(mod_ua.mutex);
 
     /* Pass to dialog. */
@@ -596 +587 @@
     pjsip_dlg_dec_lock(dlg);
 
-    /* Done processing in the UA */
-    pj_mutex_unlock(mod_ua.mutex);
-
     /* Report as handled. */
     return PJ_TRUE;
@@ -610 +598 @@
     pjsip_transaction *tsx;
     struct dlg_set *dlg_set;
-    pjsip_dialog *dlg = NULL;
+    pjsip_dialog *dlg;
+    pj_status_t status;
 
     /*
@@ -621 +610 @@
      * the response is a forked response.
      */
+
+retry_on_deadlock:
+
+    dlg = NULL;
 
     /* Lock user agent dlg table before we're doing anything. */
@@ -783 +776 @@
     rdata->endpt_info.mod_data[mod_ua.mod.id] = dlg;
 
-    /* Acquire lock to the dialog. */
+    /* Attempt to acquire lock to the dialog. */
     PJ_LOG(6,(dlg->obj_name, "UA layer acquiring dialog lock for response"));
-    pjsip_dlg_inc_lock(dlg);
+    status = pjsip_dlg_try_inc_lock(dlg);
+    if (status != PJ_SUCCESS) {
+        /* Failed to acquire dialog mutex. This could indicate a deadlock
+         * situation, and for safety, try to avoid deadlock by releasing
+         * UA mutex, yield, and retry the whole processing once again.
+         */
+        pj_mutex_unlock(mod_ua.mutex);
+        pj_thread_sleep(0);
+        goto retry_on_deadlock;
+    }
+
+    /* We're done with processing in the UA layer, we can release the mutex */
+    pj_mutex_unlock(mod_ua.mutex);
 
     /* Pass the response to the dialog. */
@@ -792 +797 @@
     /* Unlock the dialog. This may destroy the dialog. */
     pjsip_dlg_dec_lock(dlg);
-
-    /* Unlock dialog hash table. */
-    pj_mutex_unlock(mod_ua.mutex);
 
     /* Done. */

pjproject/trunk/pjsip/src/pjsua-lib/pjsua_call.c

@@ -384 +384 @@
         return PJ_FALSE;
 
+    PJSUA_LOCK();
 
     /* Verify that we can handle the request. */
@@ -408 +409 @@
         }
 
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     } 
@@ -428 +430 @@
         PJ_LOG(2,(THIS_FILE, 
                   "Unable to accept incoming call (too many calls)"));
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     }
@@ -446 +449 @@
         pjsip_endpt_respond_stateless(pjsua_var.endpt, rdata, 500, NULL,
                                       NULL, NULL);
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     }
@@ -463 +467 @@
         pjsip_endpt_respond_stateless(pjsua_var.endpt, rdata, 500, NULL,
                                       NULL, NULL);
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     }
@@ -472 +477 @@
         pjsip_endpt_respond_stateless(pjsua_var.endpt, rdata, 500, NULL,
                                       NULL, NULL);
-
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     }
@@ -500 +505 @@
         pjsip_dlg_terminate(dlg);
          */
+        PJSUA_UNLOCK();
         return PJ_TRUE;
     }
@@ -521 +527 @@
         pjsip_dlg_respond(dlg, rdata, 500, NULL, NULL, NULL);
         pjsip_inv_terminate(inv, 500, PJ_FALSE);
+        PJSUA_UNLOCK();
         return PJ_TRUE;
 
@@ -537 +544 @@
 
     /* This INVITE request has been handled. */
+    PJSUA_UNLOCK();
     return PJ_TRUE;
 }
@@ -566 +574 @@
 
 
+/* Acquire lock to the specified call_id */
+static pj_status_t acquire_call(const char *title,
+                                pjsua_call_id call_id,
+                                pjsua_call **p_call)
+{
+    enum { MAX_RETRY=50 };
+    unsigned retry;
+    pjsua_call *call;
+    pj_bool_t has_pjsua_lock;
+    pj_status_t status;
+
+    for (retry=0; retry<MAX_RETRY; ++retry) {
+        
+        has_pjsua_lock = PJ_FALSE;
+
+        status = PJSUA_TRY_LOCK();
+        if (status != PJ_SUCCESS) {
+            pj_thread_sleep(retry/10);
+            continue;
+        }
+
+        has_pjsua_lock = PJ_TRUE;
+        call = &pjsua_var.calls[call_id];
+
+        if (call->inv == NULL) {
+            PJSUA_UNLOCK();
+            PJ_LOG(3,(THIS_FILE, "Invalid call_id %d in %s", call_id, title));
+            return PJSIP_ESESSIONTERMINATED;
+        }
+
+        status = pjsip_dlg_try_inc_lock(call->inv->dlg);
+        if (status != PJ_SUCCESS) {
+            PJSUA_UNLOCK();
+            pj_thread_sleep(retry/10);
+            continue;
+        }
+
+        PJSUA_UNLOCK();
+
+        break;
+    }
+
+    if (status != PJ_SUCCESS) {
+        if (has_pjsua_lock == PJ_FALSE)
+            PJ_LOG(1,(THIS_FILE, "Timed-out trying to acquire PJSUA mutex "
+                                 "(possibly system has deadlocked) in %s",
+                                 title));
+        else
+            PJ_LOG(1,(THIS_FILE, "Timed-out trying to acquire dialog mutex "
+                                 "(possibly system has deadlocked) in %s",
+                                 title));
+        return PJ_ETIMEDOUT;
+    }
+    
+    *p_call = call;
+
+    return PJ_SUCCESS;
+}
+
+
 /*
  * Get the conference port identification associated with the call.
@@ -571 +639 @@
 PJ_DEF(pjsua_conf_port_id) pjsua_call_get_conf_port(pjsua_call_id call_id)
 {
+    pjsua_call *call;
+    pjsua_conf_port_id port_id;
+    pj_status_t status;
+
     PJ_ASSERT_RETURN(call_id>=0 && call_id<(int)pjsua_var.ua_cfg.max_calls, 
                      PJ_EINVAL);
-    return pjsua_var.calls[call_id].conf_slot;
-}
+
+    status = acquire_call("pjsua_call_get_conf_port()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return -1;
+
+    port_id = call->conf_slot;
+
+    pjsip_dlg_dec_lock(call->inv->dlg);
+
+    return port_id;
+}
+
 
 
@@ -584 +666 @@
 {
     pjsua_call *call;
+    pj_status_t status;
 
     PJ_ASSERT_RETURN(call_id>=0 && call_id<(int)pjsua_var.ua_cfg.max_calls,
@@ -590 +673 @@
     pj_bzero(info, sizeof(*info));
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (call->inv == NULL) {
-        PJSUA_UNLOCK();
-        return PJ_SUCCESS;
-    }
-
-    pjsip_dlg_inc_lock(call->inv->dlg);
-
+    status = acquire_call("pjsua_call_get_info()", call_id, &call);
+    if (status != PJ_SUCCESS) {
+        return status;
+    }
 
     /* id and role */
@@ -697 +773 @@
 
     pjsip_dlg_dec_lock(call->inv->dlg);
-    PJSUA_UNLOCK();
 
     return PJ_SUCCESS;
@@ -743 +818 @@
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (call->inv == NULL) {
-        PJ_LOG(3,(THIS_FILE, "Call %d already disconnected", call_id));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
+    status = acquire_call("pjsua_call_answer()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
 
     if (call->res_time.sec == 0)
@@ -761 +830 @@
         pjsua_perror(THIS_FILE, "Error creating response", 
                      status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -774 +843 @@
                      status);
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return status;
@@ -794 +863 @@
 
 
+    if (call_id<0 || call_id>=(int)pjsua_var.ua_cfg.max_calls) {
+        PJ_LOG(1,(THIS_FILE, "pjsua_call_hangup(): invalid call id %d",
+                             call_id));
+    }
+    
     PJ_ASSERT_RETURN(call_id>=0 && call_id<(int)pjsua_var.ua_cfg.max_calls,
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Invalid call or call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJ_EINVAL;
-    }
+    status = acquire_call("pjsua_call_hangup()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
 
     if (code==0) {
@@ -821 +889 @@
                      "Failed to create end session message", 
                      status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -830 +898 @@
      */
     if (tdata == NULL) {
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return PJ_SUCCESS;
     }
@@ -843 +911 @@
                      "Failed to send end session message", 
                      status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return PJ_SUCCESS;
@@ -867 +935 @@
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-    
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
+    status = acquire_call("pjsua_call_set_hold()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
+
 
     if (call->inv->state != PJSIP_INV_STATE_CONFIRMED) {
         PJ_LOG(3,(THIS_FILE, "Can not hold call that is not confirmed"));
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return PJSIP_ESESSIONSTATE;
     }
@@ -885 +948 @@
     status = create_inactive_sdp(call, &sdp);
     if (status != PJ_SUCCESS) {
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -893 +956 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to create re-INVITE", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -904 +967 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to send re-INVITE", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return PJ_SUCCESS;
@@ -930 +993 @@
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
-
+    status = acquire_call("pjsua_call_reinvite()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
 
     if (call->inv->state != PJSIP_INV_STATE_CONFIRMED) {
         PJ_LOG(3,(THIS_FILE, "Can not re-INVITE call that is not confirmed"));
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return PJSIP_ESESSIONSTATE;
     }
@@ -955 +1011 @@
         pjsua_perror(THIS_FILE, "Unable to get SDP from media endpoint", 
                      status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -963 +1019 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to create re-INVITE", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -974 +1030 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to send re-INVITE", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return PJ_SUCCESS;
@@ -1000 +1056 @@
                      PJ_EINVAL);
     
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
+    pjsip_dlg_dec_lock(call->inv->dlg);
+    status = acquire_call("pjsua_call_xfer()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
+
    
     /* Create xfer client subscription.
@@ -1017 +1069 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to create xfer", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -1027 +1079 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to create REFER request", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -1038 +1090 @@
     if (status != PJ_SUCCESS) {
         pjsua_perror(THIS_FILE, "Unable to send REFER request", status);
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return status;
     }
@@ -1047 +1099 @@
      */
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return PJ_SUCCESS;
@@ -1066 +1118 @@
                      PJ_EINVAL);
     
-    PJSUA_LOCK();
+    status = acquire_call("pjsua_call_dial_dtmf()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
 
     call = &pjsua_var.calls[call_id];
@@ -1072 +1126 @@
     if (!call->session) {
         PJ_LOG(3,(THIS_FILE, "Media is not established yet!"));
-        PJSUA_UNLOCK();
+        pjsip_dlg_dec_lock(call->inv->dlg);
         return PJ_EINVALIDOP;
     }
@@ -1078 +1132 @@
     status = pjmedia_session_dial_dtmf( call->session, 0, digits);
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return status;
@@ -1104 +1158 @@
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
-
-    /* Lock dialog. */
-    pjsip_dlg_inc_lock(call->inv->dlg);
-
+    status = acquire_call("pjsua_call_send_im", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
+    
     /* Set default media type if none is specified */
     if (mime_type == NULL) {
@@ -1168 +1213 @@
 on_return:
     pjsip_dlg_dec_lock(call->inv->dlg);
-    PJSUA_UNLOCK();
     return status;
 }
@@ -1184 +1228 @@
     pj_status_t status;
 
-
     PJ_ASSERT_RETURN(call_id>=0 && call_id<(int)pjsua_var.ua_cfg.max_calls,
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
-
-    if (!call->inv) {
-        PJ_LOG(3,(THIS_FILE,"Call has been disconnected"));
-        PJSUA_UNLOCK();
-        return PJSIP_ESESSIONTERMINATED;
-    }
-
-    /* Lock dialog. */
-    pjsip_dlg_inc_lock(call->inv->dlg);
-    
+    status = acquire_call("pjsua_call_send_typing_ind", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
+
     /* Create request message. */
     status = pjsip_dlg_create_request( call->inv->dlg, &pjsip_message_method,
@@ -1225 +1259 @@
 on_return:
     pjsip_dlg_dec_lock(call->inv->dlg);
-    PJSUA_UNLOCK();
     return status;
 }
@@ -1502 +1535 @@
     char tmp[128];
     char *p, *end;
+    pj_status_t status;
     int len;
 
@@ -1507 +1541 @@
                      PJ_EINVAL);
 
-    PJSUA_LOCK();
-
-    call = &pjsua_var.calls[call_id];
+    status = acquire_call("pjsua_call_dump()", call_id, &call);
+    if (status != PJ_SUCCESS)
+        return status;
 
     *buffer = '\0';
@@ -1515 +1549 @@
     end = buffer + maxlen;
     len = 0;
-
-    if (call->inv == NULL) {
-        PJSUA_UNLOCK();
-        return PJ_EINVALIDOP;
-    }
 
     print_call(indent, call_id, tmp, sizeof(tmp));
@@ -1570 +1599 @@
         dump_media_session(indent, p, end-p, call->session);
 
-    PJSUA_UNLOCK();
+    pjsip_dlg_dec_lock(call->inv->dlg);
 
     return PJ_SUCCESS;